Recent years have seen the advance of many new technologies for dispensing or discharging fluids. Particularly with the advent of improved computer and control systems, it has become possible to controllably meter very small quantities of fluids through a discharge orifice. By way of example, in the transportation field, fuel injection systems have improved such that delivery of fuel for combustion has enabled improvements in fuel efficiency and emissions. This is particularly the case for example in connection with diesel engine systems, where combustion emissions historically have been unattractive.
The increasing demand for efficient fuel injection systems has driven development of increasingly sophisticated fuel injectors. In the manufacture of such injectors there remains a need for quality control to assure that precise manufacturing tolerances and production conditions have been met for proper operation of the injectors. Additionally, as emission and performance requirements placed upon transportation vehicles continue to become more stringent, the aftermarket has seen the need for the efficient diagnosis, repair or retrofitting of existing engine fuel injection systems. In such instances, it is also necessary to assure that injector performance can be readily monitored.
To date, there have been few successful attempts to analyze fuel injectors with testing machines. One commercial example is a machine offered by Michigan Custom Machines, Inc. under the designation HEUI Injector Test Machine. Such a machine has employed a flow meter downstream of a fuel injector for analyzing the discharge of the flow meter. A first electronics system controls generation of pressure upon the fuel injector for causing discharge by the fuel injector. A second electronics system, independent of the first, is associated with the flow meter for data acquisition. The flow meter employed (available from Ono Sokki) includes an enclosed chamber of predetermined volume, into which discharge is directed and monitored by sensing changes of temperature and pressure of the discharge fluid.
It would be attractive to employ a discharge monitoring device that is robust, compact, relatively inexpensive for efficiently and reproducibly monitoring the performance of a fluid discharge device such as a fuel injector. It would also be attractive for a discharge monitoring device to employ an electronics system that communicates directly between the flow meter and any means for causing fuel injector discharge so that performance of the fuel injector can be monitored based upon actual information about the signal delivered for causing fuel injector discharge and the response of the fuel injector to the signal.